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  1. #include <stdio.h>
  2. #include <string.h>
  3. #include <ctype.h>
  4. #include <stdlib.h>
  5.  
  6. #define MAX_SYMBOLS 200
  7.  
  8. struct Symbol {
  9.     char name[100];
  10.     char type[30];
  11. };
  12.  
  13. struct Symbol symbolTable[MAX_SYMBOLS];
  14. int symbolCount = 0;
  15.  
  16. void addSymbol(const char *name, const char *type) {
  17.     for (int i = 0; i < symbolCount; ++i) {
  18.         if (strcmp(symbolTable[i].name, name) == 0)
  19.             return;
  20.     }
  21.     strcpy(symbolTable[symbolCount].name, name);
  22.     strcpy(symbolTable[symbolCount].type, type);
  23.     symbolCount++;
  24. }
  25.  
  26. void tokenize(const char *input) {
  27.     int i = 0;
  28.     char token[100];
  29.  
  30.     while (input[i] != '\0') {
  31.  
  32.         if (isspace((unsigned char)input[i])) {
  33.             i++;
  34.             continue;
  35.         }
  36.  
  37.         if (input[i] == '(' || input[i] == ')') {
  38.             token[0] = input[i];
  39.             token[1] = '\0';
  40.             addSymbol(token, "PARENTHESIS");
  41.             i++;
  42.             continue;
  43.         }
  44.  
  45.         if (strchr("|*+.-", input[i])) {
  46.             token[0] = input[i];
  47.             token[1] = '\0';
  48.             addSymbol(token, "OPERATOR");
  49.             i++;
  50.             continue;
  51.         }
  52.  
  53.         if (input[i] == '\\') {
  54.             if (input[i + 1] == 'n' || input[i + 1] == 't' || input[i + 1] == '\\') {
  55.                 token[0] = '\\';
  56.                 token[1] = input[i + 1];
  57.                 token[2] = '\0';
  58.                 addSymbol(token, "ESCAPE_SEQUENCE");
  59.                 i += 2;
  60.                 continue;
  61.             }
  62.         }
  63.  
  64.         if (input[i] == '\'' && input[i + 2] == '\'') {
  65.             token[0] = input[i];
  66.             token[1] = input[i + 1];
  67.             token[2] = input[i + 2];
  68.             token[3] = '\0';
  69.             addSymbol(token, "LITERAL");
  70.             i += 3;
  71.             continue;
  72.         }
  73.  
  74.         if (strncmp(&input[i], "lambda", 6) == 0) {
  75.             addSymbol("lambda", "EMPTY_STRING");
  76.             i += 6;
  77.             continue;
  78.         } else if (strncmp(&input[i], "null", 4) == 0) {
  79.             addSymbol("null", "EMPTY_STRING");
  80.             i += 4;
  81.             continue;
  82.         } else if ((unsigned char)input[i] == 0xCE && (unsigned char)input[i + 1] == 0xB5) {
  83.             // UTF-8 for ε
  84.             strcpy(token, "ε");
  85.             addSymbol(token, "EMPTY_STRING");
  86.             i += 2;
  87.             continue;
  88.         } else if (input[i] == 'ε') {
  89.             token[0] = 'ε';
  90.             token[1] = '\0';
  91.             addSymbol(token, "EMPTY_STRING");
  92.             i++;
  93.             continue;
  94.         }
  95.  
  96.         if (isalpha((unsigned char)input[i]) || input[i] == '_') {
  97.             int j = 0;
  98.             while (isalnum((unsigned char)input[i]) || input[i] == '_') {
  99.                 token[j++] = input[i++];
  100.             }
  101.             token[j] = '\0';
  102.             addSymbol(token, "IDENTIFIER");
  103.             continue;
  104.         }
  105.  
  106.         if (isdigit((unsigned char)input[i])) {
  107.             int j = 0;
  108.             while (isdigit((unsigned char)input[i])) {
  109.                 token[j++] = input[i++];
  110.             }
  111.             token[j] = '\0';
  112.             addSymbol(token, "NUMBER");
  113.             continue;
  114.         }
  115.         token[0] = input[i];
  116.         token[1] = '\0';
  117.         printf("Unknown token: %s\n", token);
  118.         i++;
  119.     }
  120. }
  121.  
  122. int main() {
  123.     char input[1024];
  124.  
  125.     printf("Enter a regular expression:\n");
  126.     fflush(stdout);
  127.  
  128.     if (fgets(input, sizeof(input), stdin) == NULL) {
  129.         fprintf(stderr, "Error reading input.\n");
  130.         return 1;
  131.     }
  132.  
  133.     tokenize(input);
  134. +
  135.     printf("\nSymbol Table:\n");
  136.     printf("-------------------------------------------------------------------\n");
  137.     printf("%-20s %-20s %-20s\n", "Token", "Type", "Address");
  138.     printf("-------------------------------------------------------------------\n");
  139.     for (int i = 0; i < symbolCount; ++i) {
  140.         printf("%-20s %-20s %p\n", symbolTable[i].name, symbolTable[i].type, (void*)&symbolTable[i]);
  141.     }
  142.     printf("-------------------------------------------------------------------\n");
  143.  
  144.     return 0;
  145. }
  146.  
Success #stdin #stdout #stderr 0.03s 6936KB
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Standard output is empty
stderr
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ERROR: /home/yA14kD/prog:145:1: Syntax error: end_of_file_in_quasi_quotation
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/ZySfKh
language:
Prolog (swi 7.6.4)
created:
17 hours ago
visibility:
public

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